Voltage-gated calcium (Ca2+) channels play a central role in neuronal function and are essential for converting electrical activity into biochemical events. The main goal of this proposal is to identify the molecular mechanisms by which voltage-gated calcium channels activate signaling cascades that mediate gene expression and promote neuronal survival. Neurons and muscle cells express at least ten different kinds of voltage-gated calcium channels that vary in their subcellular localization and biophysical properties. L-type channels (LTCs) are particularly effective at activating transcriptional pathways and at promoting neuronal survival. The transcription factors CREB and MEF-2 are two important targets of LTC signaling that regulate differentiation and plasticity in the nervous system. The biophysical and biochemical features that allow LTCs to activate gene expression and suppress apoptosis are not well understood. To address the question of how LTCs are linked to signaling pathways the following specific aims are proposed: 1) To determine the structural and biophysical features that allow L-type calcium channels to activate transcription. 2) To determine whether specific L-type channel interacting proteins link the channel to signaling pathways that lead to the activation of transcription. 3) To determine what features of L-type calcium channels allow them to inhibit neuronal apoptosis and promote survival. Biochemical, cell biological and electrophysiological techniques will be used to develop these specific aims. We have recently developed a method of using dihydropyridine insensitive LTCs to investigate LTC signaling in primary neurons and we plan to use this approach for these studies. We have also identified several LTC-interacting proteins that may be important for channel regulation and signaling and we plan to investigate their importance for signaling to the nucleus. The results of these experiments will provide critical insights into how voltage-gated channels activate the signaling pathways that regulate the structure and function of the nervous system.